Mio Sakamoto is a seasoned military officer and former witch from Fuso, affiliated with the Fuso Imperial Navy. She served as commanding officer of the 501st Joint Fighter Wing and is sometimes known by the alias Samurai. A first-class veteran witch, she gained recognition during early Neuroi encounters such as the Fuso Sea Incident in 1937. Early in her career, she trained under Kitagou Fumika and maintained a rivalry with Wakamoto Tetsuko. She was among the first test pilots for Striker Units using Miyafuji theory and underwent training in Romagna under Anna Ferrara, whom she found difficult. Deployed to Britannia before the Neuroi's full-scale invasion, she contributed to the development of the Type 0 Striker Unit and became acquainted with Dr. Miyafuji. After the invasion began, she remained in Europe with the Fuso Imperial Navy European Dispatch Fleet Libau Flying Corps, defending Libau until its evacuation. She sustained an injury there that forced a temporary return to Fuso. She was part of the "Libau Triumvirate" alongside Pilot Officer Takei and Nishizawa Yoshiko. Originally a Flight Lieutenant, she was promoted to Squadron Leader due to achievements with the 501st. After the unit disbanded following Gallia's liberation, she worked briefly as a temporary instructor at a Navy Witches training academy before retiring three months later. She continued training to fight with diminished magic power, reuniting with comrade Kuroe Ayaka after seven years. During a mock battle, she demonstrated the secret sword technique "Unyou," which later facilitated acquiring "Reppuzan." She forged the magic-infused Fuso sword Reppumaru to compensate for her weakening magic shield. During the final battle against the Neuroi Super-Hive in Venezia, her depleted magic power prevented effective use of Reppuzan. She used her remaining magic to charge the magic dynamo of the Yamato, leading to the destruction of the Super-Hive's outer shell. Absorbed by the Neuroi-fied ship, she was saved by Sergeant Miyafuji's sacrifice, who performed a Shin Reppuzan to destroy the core. After eight years fighting the Neuroi, she retired as a witch due to complete loss of magical power but remained in the military to support her comrades. She gained a reputation as a strict but adored teacher who reared several excellent witches. Her personality is broad-minded, cheerful, and candidly mannish. She is faithful to moral obligations and humane feelings, often sentimental, with a favorite motto: "simplicity and fortitude." She is hot-blooded yet cool and elaborate in battle, always seeking solutions without giving up. She enjoys hot springs and is easily moved to tears but avoids crying in front of others. Unaware of the admiration she receives, she interprets attention from subordinates such as Flying Officer Clostermann as diligence rather than special favor. Having enrolled in the military early, she has no food preferences and will eat anything edible but is not skilled at cooking. Her inherent magic is Magic Eye (魔眼, Magan), a perception-lineage ability granting her right eye super eyesight to discern distant objects and see through domains normally imperceptible. Limited to her field of vision, it cannot see past obstacles or dense clouds, is limited at night, and requires an eye-patch to control as it is permanently active. When her magic power is low, her right eye functions normally. By combining her enchanted sword Reppumaru with excellent swordsmanship, she acquired Reppuzan, a technique concentrating magic power into the blade to release a slicing wave of magical energy. Extremely difficult for her, it belongs to the telekinetic magic class, not her innate type. She excels at evading Neuroi beams by "seeing through" them and later developed the ability to slice beams in half with Reppumaru as a defensive measure when she could no longer use magic shields. She excels in leadership and training, guiding both subordinates and superiors. Strict in training due to her fear of losing comrades, she maintains a collection of training equipment and feels responsible for rearing Sergeant Miyafuji Yoshika, the daughter of Dr. Miyafuji, to whom she is indebted. Her Striker Units include the Miyabishi Type 0 Carrier-based Fighter Legs Model 21 (No. V-128) used in Libau, the Yamanishi Shiden Model 21 (No. ヨ-104) used during model conversion training in Yokosuka, and the Yamanishi Shiden Model 53, a latest model prototype with a Ma43 engine and slight modifications. In combat, she used a Type 99-2 Model 2 Kai heavy machine gun and carried two swords, including Reppumaru. Her historical inspiration is attributed to the Japanese flying aces Sakai Saburo, known as the "Sky Samurai," and Tetsuzō Iwamoto. She appears in various media including anime series, films, OVAs, light novels, manga, and video games such as Strike Witches, Strike Witches 2, Strike Witches Movie, Operation Victory Arrow, and Road to Berlin.